Since plastic lenses are lightweight and unlikely to be cracked compared to inorganic lenses and can be dyed, in recent years, plastic lenses have been rapidly spreading as optical materials such as spectacle lenses or camera lenses.
Glass has been mainly used as a material of an optical material. However, in recent years, various kinds of plastics for an optical material have been developed and broadly used as a substitute for glass. From the viewpoints of having excellent optical characteristics, being lightweight, being unlikely to be cracked, and having excellent moldability, plastic materials such as an acrylic resin, an aliphatic carbonate resin, polycarbonate, and polythiourethane have been mainly used as the materials of spectacle lenses. Among these, a polythiourethane resin obtained from a polymerizable composition containing an isocyanate compound and a thiol compound is exemplified as a representative example of the material with a high refractive index (Patent Document 1).
In recent years, due to a change in life style, people who enjoy moving their bodies by playing sports or the like while wearing glasses have been increasing. Further, due to an increase in safety consciousness, there has been an increasing demand for children's glasses which are unlikely to be cracked. Under these circumstances, there has been a strong demand for a base material which is lightweight and has excellent impact resistance. In response to these strong demands, a urethane urea resin has been developed for spectacle lens applications as a base material with excellent impact resistance (Patent Documents 2 to 7). In addition, a thiourethane urea resin (Patent Documents 8 to 12) containing an amine compound, an isocyanate compound, and a thiol compound is suggested as a lens material which achieves both of excellent impact resistance and a high refractive index, and a polyurethane resin (Patent Documents 13 and 14) containing an amine compound, an isocyanate compound, and a polyol compound is suggested as a lens material which has excellent impact resistance and chemical resistance.